Grade 3 • Module 2 - Smithtown Central School Districtmoodle.smithtown.k12.ny.us/pluginfile.php/37851/mod...Grade 3 • Module 2 Place Value and Problem Solving with Units of Measure

Grade 3 • Module 2

Place Value and Problem Solving with Units of Measure

OVERVIEW

In this 25-day module, students explore measurement using kilograms, grams, liters, milliliters, and

intervals of time in minutes. Students begin by learning to tell and write time to the nearest minute

using analog and digital clocks in Topic A. They understand time as a continuous measurement through

exploration with stopwatches and use the number line, a continuous measurement model, as a tool for

counting intervals of minutes within 1 hour. Students see that an analog clock is a portion of the

number line shaped into a circle. They use both the number line and clock to represent addition and

subtraction problems involving intervals of minutes within 1 hour.

Kilograms and grams are introduced in Topic B, measured on digital and spring scales. Students use

manipulatives to build a kilogram and then decompose it to explore the relationship between the size

and weight of kilograms and grams . An exploratory lesson relates metric weight and liquid volume

measured in liters and milliliters, highlighting the coherence of metric measurement. Students practice

measuring liquid volume using the vertical number line and graduated beaker. Building on Grade 2’s

estimation skills with metric length, students in Grade 3 use kilograms, grams, liters, and milliliters to

estimate the liquid volumes and weights of familiar objects. Finally, they use their estimates to reason

about solutions to one-step addition, subtraction, multiplication, and division word problems involving

metric weight and liquid volume given in the same units.

More experienced with measurement and estimation using different units and tools, students further

develop their skills by learning to round in Topic C. They measure, and then use place value

understandings and the number line as tools to round two-, three-, and four-digit measurements to the

nearest ten or hundred.

Students measure and round to solve problems in Topics D and E. In these topics they use estimations

to test the reasonableness of sums and differences precisely calculated using standard algorithms. From

their work with metric measurement students have a deeper understanding of the composition and

decomposition of units. They bring this to every step of the addition and subtraction algorithms with

two- and three-digit numbers as 10 units are changed for 1 unit or 1 unit is changed for 10 units. Both

topics end in problem solving involving metric units or intervals of time. Students round to estimate,

and then calculate precisely using the standard algorithm to add or subtract two- and three-digit

measurements given in the same units.

Terminology

New or Recently Introduced Terms and Symbols

About (with reference to rounding and estimation, an answer that is not precise)

Addend (the numbers that are added together in an addition equation, e.g., in 4 + 5, the numbers 4 and 5 are the addends)

Analog clock (a clock that is not digital)

Capacity (the amount of liquid that a particular container can hold)

Compose (change 10 smaller units for 1 of the next larger unit on the place value chart)

Continuous (with reference to time as a continuous measurement)

Endpoint (used with rounding on the number line; the numbers that mark the beginning and end of a given interval)

Gram (g, unit of measure for weight)

Halfway (with reference to a number line, the midpoint between two numbers, e.g., 5 is halfway between 0 and 10)

Interval (time passed or a segment on the number line)

Kilogram (kg, unit of measure for mass)

Liquid volume (the space a liquid takes up)

Liter (L, unit of measure for liquid volume)

Milliliter (mL, unit of measure for liquid volume)

Plot (locate and label a point on a number line)

Point (a specific location on the number line)

Reasonable (with reference to how plausible an answer is, e.g., “Is your answer reasonable?”)

Rename (regroup units, e.g., when solving with the standard algorithm)

Round (estimate a number to the nearest 10 or 100 using place value)

Second (a unit of time)

Standard algorithm (for addition and subtraction)

≈ (Symbol used to show than an answer is approximate)

Familiar Terms and Symbols Centimeter (cm, unit of measurement)

Divide (e.g., 4 ÷ 2 = 2)

Estimate (approximation of the value of a quantity or number)

Horizontal (with reference to how an equation is written, e.g., 3 + 4 =7 is written horizontally)

Measure (a quantity representing a weight or liquid volume, or the act of finding the size or amount of something)

Mental math (calculations performed in one’s head, without paper and pencil)

Meter (m, unit of measurement)

Minute (a unit of time)

Multiply (e.g., 2 × 2 = 4)

Number line (may be vertical or horizontal)

Simplifying strategy (transitional strategies that move students toward mental math, e.g., “make ten” to add 7 and 6, (7 + 3) + 3 = 13)

Unbundle (regroup units, e.g., in the standard algorithm)

Vertical (with reference to how an equation is written; equations solved using the standard algorithm are typically written vertically)

Ten-frame

2

Vertical number

Lesson 1

Objective: Explore time as a continuous measurement using a stop-watch.

Remember fastest means the shortest amount of time. Students can use timers on cell

phones, microwaves, or counting seconds to determine what activities they can do in a set

amount of time.

Remember to practice multiplication facts. Try to memorize them in order3x1=3, 3x2=6,

3x3=9 and so on. Students can skip count both up and down to reinforce fluency.

Lesson 2

Objective: Relate skip-counting by 5 on the clock and telling time to a

continuous measurement model, the number line.

Think about a clock as a circular number line. If we stretch it out it looks like the number

line below.

Sprints– 10:10

Application Problem– 10:20

Exit Ticket– 10:50

Lesson 3

Objective: Count by fives and ones on the number line as a strategy to

tell time to the nearest minute on the clock.

You can add 4 smaller marks

between each 5 minute marks to

identify time to the minute.

Lesson 4

Objective: Solve word problems involving time intervals within 1 hour

by counting backward and forward using the number line and clock.

Remember to count up

how many skip count by

ones and fives to find the

total elapsed time.

Lesson 5

Objective: Solve word problems involving time intervals within 1 hour

by adding and subtracting on the number line.

Gia, Carlos’s classmate, gets to class at 9:11. It takes her 19 minutes to write homework

assignments and complete morning work. How can we figure out if Gia will be ready to start

math at

9:30?

We can start

at 9:11 and add 19 minutes. We can add 11 minutes and 19 minutes to find out how many

minutes after 9:00 she finishes .

11 minutes + 19 minutes = 30 minutes

Gina will be ready to start math at 9:30

Lesson 6

Objective: Build and

decompose a kilogram to

reason about the size

and weight of 1

kilogram, 100 grams, 10

grams, and 1 gram.

Lesson 7

Objective: Develop estimation

strategies by reasoning about the

weight in kilograms of a series of

familiar objects to establish mental

benchmark measures.

Lesson 8

Objective: Solve one-step word problems involving metric weights with-

in 100 and estimate to reason about solutions.

Use a tape diagram,

count on, decompose, or

other methods to solve

problems. Remember to

write an equation to match your models.

Lesson 9

Objective: Decompose a liter to reason about the size of 1 liter, 100 mil-

liliters, 10 milliliters, and 1 milliliter.

One mL is can be measured One liter and be thought of as a bottle

with an eye dropper of water

Lesson 10

Objective: Estimate

and measure liquid

volume in liters and

milliliters using the

vertical number line.

When estimating think

about what number it is

closest too.

Lesson 11

Objective: Solve mixed word problems involving all four operations with grams,

kilograms, liters, and milliliters given in the same units.

Decompose to add and subtract Use tape diagrams to multiply or divide

Lesson 12

Objective: Round two-digit measurements to the nearest ten on the vertical

number line.

Think about the vertical number line when

rounding. If you are halfway to the next unit or

more, round up to the next unit. If it is less than

halfway to the next unit, round down to the

lesser unit.

Lesson 13

Objective: Round two-

and three-digit

numbers to the

nearest ten on

the vertical

number line.

Lesson 14

Objective: Round to the nearest hundred on the vertical

number line.

Lesson 15

Objective: Add measurements

using the standard algorithm to

compose larger units once.

Lesson 16

Objective: Add measurements using the standard algorithm to compose larger

units twice.

Some problems may require us to add more then once. Sometimes you can

Always ask yourself “is my answer reasonable?” distribute to make

benchmark numbers.

Lesson 17

Objective: Estimate sums by rounding and apply to

solve measurement word problems.

Lesson 18

Objective: Decompose once to subtract measurements including three-

digit minuends with zeros in the tens or ones place.

There are different approaches to subtraction problems. Students are encouraged to use

the one they feel suits them best.

Lesson 19

Objective: Decompose twice to subtract measurements including three-digit

minuends with zeros in the tens and ones

places.

Lesson 20

Objective: Estimate differences by

rounding and apply to solve

measurement word problems.

Before we round we look at the numbers to

see what type of rounding will get me a

reasonable answer. Should I round to the

tens or hundreds?

Lesson 21

Objective: Estimate sums and differences of measurements by rounding, and

then solve mixed word problems.